The PC has 2 Ethernet cards. One is build in into mother boards (Asus x470f) other one is Asus xg-c100c. I connect it into switch from Asus xg-c100c card. Switch is connected to ISP provided router-switch-modem-access_point, the typical all-in-one router with DSL/FIBER modem.

Current switch is cheapo I bought used from coworker, I would need to buy new one anyway.
In network there are many other devices (3 laptops, 3 consoles, TV, printer and smarthones and one Intel NUC working 24/7). The diagram shows only switch/router/PC/NAS.

I do not like what ISP has provided me, but the only other option is to use it, turn off wi-fi and use my own router, but that would create problems like double NAT, so I would probably opt from it.